Denver Broncos

Where we left off: This was one of the worst teams in the NFL in 2010, but there is nowhere to go but up. Josh McDaniels led a club that could score some points, but too much of it was in garbage time after the aging defense had surrendered several scores. When the Broncos were in a tight game, the anemic ground attack (26th in NFL) provided little support. The fact that Denver castoff Peyton Hillis had a monster year running the ball for Cleveland didn't help. Ultimately, McDaniels was fired and the short-lived Eric Studesville administration followed. Now the John Fox era begins, with one task being pretty clear: shore up the league´s worst defense. Denver gave up 390.8 yards per game. That's terrible.

Areas of concern: Fox's defense will be of the 4-3 variety, not a 3-4, with the organization having its fourth defensive coordinator in as many years. With more changes could come some growing pains, especially for top-pick linebacker Von Miller, who is expected to start right out of the gate. Ditto the rest of the rookies, as Denver took six defensive players in April's draft. A healthy Elvis Dumervil sure would help, as Denver sorely missed his presence last season. Of course, the big elephant in the room at the team offices is what to do at quarterback, where the Johns (Elway and Fox) could go with the young Tim Tebow or the productive Kyle Orton. Either way, this team needs to get more out of running back Knowshon Moreno, as well as a steady player to complement him.

Two things to hang your hat on, Broncos fans: 1. Brandon Lloyd is no fluke. Forget the numbers. Some of the catches he made only 15 people on the planet could've even thought about making. He's a mature man, not a 22 year old anymore. 2. With Fox's arrival comes respect from the locker room and around the league. All of the drama that surrounded the McDaniels era won't have a sequel here.

Kansas City Chiefs

Where we left off: This club got crushed in the playoff loss to the Ravens. Can the Chiefs make it back? They rode a 10-6 record to an AFC West title with an outstanding running game, solid quarterback play, and a defense that created big plays. Problem was, that defense could give 'em up too, like in key losses to the Texans, Chargers, and, of course, the Ravens. Still, this team is loaded with young talent, from Dwayne Bowe and Jamaal Charles on offense, to Eric Berry and Tamba Hali on defense. Don't look for this team to fail miserably in 2011.

Areas of concern: Defensively, the Chiefs need some other guys to step up outside of Berry and Hali. That starts with Glenn Dorsey and Wallace Gilberry on the line, who have really improved, but they need a solid nose tackle next to them. Gilberry, despite being an undrafted free agent, might have been the Chiefs' best defensive lineman last season. The linebacker play was much better (especially Hali), but they would be more effective if the defensive line could pick it up a notch. In fact, better play up front would give the whole defense a tremendous lift, especially considering the back four (Brandon Carr, Brandon Flowers, Kendrick Lewis, and Berry) is pretty solid. Kansas City only allowed 5.68 yards per pass, fifth in the league. Speaking of the passing game, the Chiefs need a solid second receiver. Will it be rookie Jonathan Baldwin? Age on the offensive line is also a growing issue.

Two things to hang your hat on, Chiefs fans: 1. Only three rookies made the "Top 100: Players of 2011" and one of them wears 29 in red, yellow and white. For all the hubbub about Ndamukong Suh, don't sleep on Berry. He can play. 2. Matt Cassel made huge strides last year, starting with a 27-7 touchdown-to-interception ratio. If he continues, the Chiefs will be back in the postseason.

NFL.com experts investigate the pressing issues facing each team when the lockout ends:

Oakland Raiders

Where we left off: Did anyone happen to notice that the Raiders went 6-0 in the AFC West? Talk about an under-the-radar team. The 8-8 record was more than just a step forward, it marked the first time Oakland didn't have double-digit losses since the Super Bowl season of 2002. The improvement starts with Darren McFadden, who averaged 128 yards from scrimmage per game, second in the NFL. Jason Campbell was mostly steady (only eight interceptions), while his favorite target -- Zack Miller -- continues to be one of the best kept secrets in the NFL with 60 catches for the second straight season.

Areas of concern: While the defense was pretty good (11th in NFL) and was able to get to the quarterback with 47 sacks, the unit must generate more turnovers for this team to make the playoffs. And, if Oakland loses shutdown corner Nnamdi Asomugha in free agency, opposing teams will feel comfortable attacking both sides of the field. Either way, Oakland's corners have to capitalize on opportunities to pick the ball off. Asomugha didn´t get interceptions because quarterbacks would go an entire half without testing him. Speaking of the passing game, the Raiders' receivers still don't give the team enough pop. Louis Murphy is okay, but the entire group of wideouts combined for 111 catches between them. Roddy White caught 115 balls by himself. Darrius Heyward-Bey, Hue Jackson needs something from you. Anything.

Two things to hang your hat on, Raiders fans: 1. Don't ever forget about Richard Seymour. The man is an impact player whether he lines up inside or outside, and gives the team a chip on its shoulder. 2. Rookie linebacker Rolando McClain was no disappointment, with 85 tackles, six passes defensed and a pick. His play in pass coverage was better than expected.

San Diego Chargers

Where we left off: One of the weirdest seasons in NFL history went down in San Diego last year. How a team finishes first in team offense and team defense, but can't even survive its weak division is anyone's guess. The Chargers were done in by five blocked punts, 16 lost fumbles, and an inconsistent run game, which averaged fewer than four yards per carry. The Marcus McNeill and Vincent Jackson offseason distractions got the season started off on the wrong foot. That said, the special teams breakdowns came at the worst times, and spoiled what should have been another division title for the Bolts. Also marred was another standout year (4,710 yards and 30 touchdowns) from Philip Rivers.

Areas of concern: New special teams coach Rich Bisaccia was hired in January to rectify that unit's problems. Also of concern is the passing game, which needs free agents Vincent Jackson and Malcolm Floyd back, or else Antonio Gates will be blanketed like never before. The Chargers did draft local Vincent Brown from San Diego State in the third round as insurance, and Jackson will likely be playing in San Diego in 2011 after getting franchised. Another free agent concern is safety Eric Weddle, who was one of the club's most consistent performers. The defense, as a whole, was good at getting to the pocket, with 47 sacks, but the lack of takeaways really hurt the team. Of course, the top issue with fans is Norv Turner who, if he goes 9-7 again, could be looking at his last season in San Diego.

Two things to hang your hat on, Chargers fans: 1. A lot of the players who came through NFL Network's doors for "The Top 100" show felt Rivers was as good as Aaron Rodgers or Drew Brees. He's a legit top-three quarterback in the NFL. 2. Rookie Ryan Mathews showed flashes despite gaining only 678 yards rushing, and barring injury, should have a breakout year. That would take pressure off Rivers, as well as eat up clock for the defense's sake.

Elliot Harrison is the research analyst for NFL RedZone on NFL Network.